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T104 - Arc Flash Hazards and Arc Resistant
Equipment- Understanding the Standards
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Agenda
5. Minimizing Exposure to Arc Flash Hazards
4. Field Implementation of Arc Resistant Equipment
3. Arc Resistant Equipment Rating Basics
2. Related Electrical Safety Standards
1. Background
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Agenda
5. Minimizing Exposure to Arc Flash Hazards
4. Field Implementation of Arc Resistant Equipment
3. Arc Resistant Equipment Rating Basics
2. Related Electrical Safety Standards
1. Background
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Arc Flash & Arc Blast
Up to 35,000°F/ 19,500°C
Intense Light
Copper Vapors
(Expansion rate 67,000
times)
Shrapnel Molten Metals
Sound/ Pressure
Waves
Intense Heat
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Summary of Electrical Hazards
Electrical Shock
When electrical current enters and exits the body – through a conductive path
Arc Flash
The conditions associated with the energy released by an electric arc
Includes a broad spectrum of electromagnetic energy, heat, plasma, smoke & a spray of molten materials
Arc Blast
The pressure wave caused by the expansion of gases and conducting materials within the flying molten materials
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Why the interest?
Workers are still injured or killed each year by arc
flash events while working on or near energized
equipment
Many of these casualties are as a result of burn
injuries related to the arc flash event
Unfortunately, working on energized equipment still
is commonplace in many industries
Some still ignore the need for proper personal
protective equipment (PPE)
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Why is there such focus on Electrical Safety?
Injuries and Fatalities Associated with Electrical Hazards
• Electrocution is the third leading cause of workplace fatalities in the
USA
• Electric Shock and burns are still a leading cause for lost time
– [Arc flash injuries are counted as burn Injuries]
• ~2,000 workers are treated in specialized burn trauma centers each
year as a result of reported Arc Flash injuries.
• ~every 40 minutes, a worker suffers an electrical injury that requires
time-off work!Information that is derived from Industry Surveys, the NFPA, ESFi, The National Safety Council, Bureau of Labor Statistics and CapSchell, Inc.
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Agenda
5. Minimizing Exposure to Arc Flash Hazards
4. Field Implementation of Arc Resistant Equipment
3. Arc Resistant Equipment Rating Basics
2. Related Electrical Safety Standards
1. Background
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The general
guidelines &
enforcement
policies
Guidance for
the proper
installation &
wiring of
equipment
Protection
from
electrical
hazards in
the workplace
Consensus
standard
development
Agencies & Standards that Govern Electrical Safety
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State and Federal Regulations
Occupational Safety & Health Act – USA
OSHA 1910 Subpart S
Electrical Safety Related Work Practices
Title 29 (CFR), Part 1910.331 .335
Design Safety Standards for Electrical Systems
Title 29 (CFR), Part 1910.302 .308
In Canada;
Provincial Occupational Health & Safety Acts
Each individual Canadian Province has their own act
No common act across the whole country
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Installation Codes & Standards
National Electrical Code (NEC)- 2017 (NFPA 70)
Canadian Electrical Code (CEC) - 2015 (C22.1)
Electric codes and other safety codes are primarily concerned with protection from fire, electrocution and shock hazard
Arc flash hazards first introduced in 2002 editions
On-going refinements have improved these standards regarding arc flash
Now contain direct links to other safety standards like NFPA-70E and Z-462
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NFPA-70E
First published in 1979 as “NFPA 70E Standard for Electrical Safety
Requirements for Employee Workplaces”
2004 (seventh edition), name changed what we know today
Now updated on a 3-year cycle NEW
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So what’s changed in NFPA-70E 2018?
The 2018 edition is now in effect…previous editions become
obsolete
So what’s changed…
A modified arc flash hazard identification table130.7(C)(15)(A)(a)]*
Easier to determine the likelihood that an arc flash could occur
Article 120 reorganizes the requirements for establishing an
electrically safe work condition in a logical order of application
Article 320 introduces voltage thresholds of 100 Vdc for batteries
and battery rooms to cover unique battery situations
Article 330 extensively revised to focuses on safety-related issues
for laser-based systems
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So what’s changed in NFPA-70E 2018?
Term- “Second degree burn” has been removed and replaced with “at which the incident energy equals 1.2 cal/cm2” (Stoll Curve)
The 2015 edition stated that when the incident energy exceeded 40 cal/cm2
that “greater emphasis was needed for de-energizing”
Has been deleted and replaced with a strong emphasis being placed on de-energizing at all times!
This does not only apply to 40 cal/cm2 and above
And hundreds of smaller changes/revisions*
Previous references may be different now!
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Canadian Electrical Safety Standard -CSA Z462
CSA-Z462 was originally developed in parallel with and
harmonized to NFPA 70E-2009
Directly referenced in the Canadian Electrical Code
(CEC) and is consistent with OSHA data
Z462-15 aligned to NFPA 70E-2015
Z462-18 to be available in early 2018
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Understanding the Regulatory Framework in the USA
Interplay between OSHA's electrical safety regulations, the NEC, and
NFPA-70E should be the basis of your electrical equipment systems and
safety programs
OSHA's electrical safety regulations draw heavily on the consensus
standards like NFPA-70 (NEC) and NFPA-70E, but there are some
important distinctions
Compliance with the NEC and NFPA-70E does not always equate to full
compliance with all OSHA regulations!
OSHA 1910 Subchapter S = “Shall”
NFPA-70E = “How & When”
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How are OSHA and NFPA-70E linked?
“…Industry consensus standards can be evidence that there is a hazard for which PPE is "necessary." While the NFPA 70E consensus standard has not been adopted as an OSHA standard, it is relevant as evidence that Arc Flash is a recognized hazard and that PPE is necessary to help protect against that hazard….” OSHA
“…A flash hazard analysis shall be done to help protect personnel from the possibility of injury by an Arc Flash. The analysis shall determine the Flash Protection Boundary and the Personal Protective Equipment that people within the Flash Protection Boundary shall use…” OHSA & p/o. NFPA-70E
Failure to help protect workers will result in OSHA using its authority to prosecute to
the fullest extent of the law, based on these premises
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What is Needed for Full Compliance?
A well written and audited electrical safety program
Policies and procedures aligned to the standards
Electrical safety training program
An arc flash assessment per NFPA-70E-2018 sec. (130.5)
Tasks involving an arc flash hazard
Proper equipment installation & maintenance/records (Ref NFPA-70B)
Clearly defined methods to identify electrical hazards
Labeling, color coding, pictograms, etc.
Proper electrical personal protective equipment based on the arc flash assessment
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Compliance Requirements in NFPA 70E-2018
Your Electrical Safety Program must be audited at intervals
not to exceed 3 years[70E-2018, Sec. 110.1(K)(1)]*
Safety Retraining and Assessments for all electrical workers
every 3 years or less * [70E-2018, Sec. 110.2(A)(3)]
Arc Flash Risk Assessments (Study) at intervals not to exceed
5 years*[70E-2018, Sec. 130.5(2)(f)]
* You must be able to prove compliance to these points if OHSA
audits your sites
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Agenda
5. Minimizing Exposure to Arc Flash Hazards
4. Field Implementation of Arc Resistant Equipment
3. Arc Resistant Equipment Rating Basics
2. Related Electrical Safety Standards
1. Background
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What is Arc Resistant Equipment?
Controls the exposure and release of the dynamic elements associated with an arc flash/blast event
Capabilities defined by how;
The arc flash elements are extinguished or controlled
The equipment helps prevent serious injuries to personnel
The equipment helps prevent propagating of the event
Generally, protection applies only when all equipment doors are closed and latched
Our MV ArcShield™ products provide an enhanced level of arc resistant capabilities
Testing must be done to validate the level of protection
Defined by the Accessibility Level, for example, Type 2B
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Common Arc Resistant Testing Guides & Standards CSA C22.2 NO. 0.22-11 “Evaluation Methods for Arc Resistance ratings of Enclosed Electrical
Equipment”
EEMAC G14-1-1987 “Procedure for Testing the Resistance of Metal-Clad Switchgear under Conditions of Arcing Due to an Internal Fault”
IEC 62271-200:2011 “AC Metal-Enclosed Switchgear and Controlgear for Rated Voltages Above 1 kV and up to and Including 52 kV”, Annex A - Internal Fault
IEC 61641-2014 “Enclosed low-voltage switchgear and controlgear assemblies – Guide for testing under conditions of arcing due to internal fault”
IEEE C37.20.7-2007 "IEEE Guide for Testing Metal-Enclosed Switchgear Rated Up to 38 kV for Internal Arcing Faults”
Many global guides, procedures and standards are available for AR
equipment testing
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IEEE C37.20.7-2007 Testing Guide
IEEE C37.20.7-2007 “IEEE guide for testing metal-enclosed switchgear rated up to 38 kV for internal arcing faults”
• Primarily a medium voltage testing guide
• Expanded to include some low voltage switchgear components
• Defines test criteria and compliance assessment
• Defines the levels of Arc Flash protection
• Sets expectations of arc resistance performance related to the interaction with personnel
IEEE C37.20.7-2007 is the most recognized North American Testing Guide that
applies to MV and some LV equipment
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Advantages of Arc Resistant Equipment-NFPA 70E-2018 compliance
Table 130.7(C)(15)(A)(b)- ref. Arc Flash PPE Category
Recognition of AR equipment began in the 2012 edition…
Now fully defined in 2018!
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Arc Resistant Rating Basics
So how do you know what rating is the correct rating for your system?
Consider the short circuit current level at the point of the equipment’s
use, your arc flash assessment (study) will give you this info
How long do you think your system can sustain an arcing fault?
Longer the time = greater release of energy
Longer the time = higher degrees of internal damage
A complete arc flash assessment, including a coordination study, provides
the incident energy levels (data for labeling)
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Items to Consider When Writing Your Specifications for AR Equipment
Duration Rated or Device Limited?
What arc current rating and what duration do you need?
20kA- 100ms, 30kA- 200ms, 40kA- 500ms ,50kA- 500ms…etc.
What Accessibility Type works best for your Safety Program?
Type 1, 2, 2B, etc.
Will there be a mix of equipment from various vendors?
Can I still get top & bottom entry cables?
Some vendors cannot support both
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Agenda
5. Minimizing Exposure to Arc Flash Hazards
4. Field Implementation of Arc Resistant Equipment
3. Arc Resistant Equipment Rating Basics
2. Related Electrical Safety Standards
1. Background
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Arc Resistant Installation Considerations
More preparatory planning required
Where is the equipment to be installed?
Existing or new room/building?
Overhead clearances required?
For MV equipment, overhead clearance required to accommodate arc
plenums or arc ducting system-duct outside or inside?
Are there existing cables, conduits or HVAC ducting in the area?
Will there be non-arc resistant equipment in the same area?
How will the differences be identified to workers?
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Arc Resistant Installation Considerations
Has your contractor ever installed arc resistant equipment before?
Make sure your installation specifications outline the equipment design and installation requirements
Inform your contractor that no holes can be cut without approval Verify all cover plates are reinstalled per the manufacturers
recommendations Do not compromise the safety integrity of your
investment! Audit the final installation (req. NFPA-70E-18)
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Agenda
5. Minimizing Exposure to Arc Flash Hazards
4. Field Implementation of Arc Resistant Equipment
3. Arc Resistant Equipment Rating Basics
2. Related Electrical Safety Standards
1. Background
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Are the Standard & Equipment Changes Making an Impact?
Fatal Non-Fatal
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How can Rockwell Automation support your needs?
Rockwell Automation can also provide comprehensive services to assess and enhance the Arc Flash Safety within your facilities
Arc Flash Risk Assessments
Power System Coordination Studies
Electrical Hazard Risk Assessments
Field Labeling Review/Implementation
Mitigation/Re-Engineering Services
Arc Flash Program Agreements
Training & Maintenance Agreements
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NEMA ArcShield™ MV MCC Arc Resistant Controls (to 7.2 kV)
Tested to IEEE C37.20.7
40kA or 50 kA (@ 7.2 kV), for ½
second
Type 2B Accessibility
Protection maintained even with LV
doors open
Personnel are shielded at the front,
rear and sides of enclosure
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OneGear™ IEC Arc Resistant ControlsMedium Voltage Soft Starters to 15 kV
OneGear IEC 15 kV Controlgear Arc resistant to IEC 602271-200
31.5 kA @ 14.4 kV, ½ sec.
Accessibility- AFLR
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Arc Resistant Medium Voltage ASD
First AR MV Drive with
full regeneration
capabilities
Tested to IEEE C37.20.7
40kA or 50kA arc
resistant systems
available
Up to 7.2 kV rated
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ArcShield NEMA and IEC Low Voltage Motor Control Centers
CENTERLINE® 2100 Low Voltage
NEMA motor control center with ArcShield™
First arc resistant NEMA low voltage MCC
IEEE C37.20.7 Type 2 Accessibility
CENTERLINE 2500 Low Voltage
IEC motor control center with ArcShield™
Personnel and assembly protection
per,
IEC 61641:2008
IEC/TR 61641, Edition 3.0 2014
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Bulletin 857/865 Protection Systems
Bulletin 865
Differential Protection System
Bulletin 857
Motor/Feeder Protection System
Both available with an available Arc
Flash Detection option
Combined optical and current
signature sensing technology
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Minimize Exposure with ArcShield & IntelliCENTER® Technology
Enhanced network capabilities
EtherNet/IP based
IntelliCENTER software allowing for
remote monitoring, configuring and
troubleshooting remotely - No need to
be near the equipment
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Summary
These standards, regulations and arc resistant control products
are Enhancing Personnel Safety, creating a safer work
environment for all!
Ultimately we are reducing the number of injuries and fatalities
caused by electrical hazards!
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Summary- some references
Sound Safety principles in action
Arc Flash/Blast are explosive events
4X hotter than the sun
Sources >125 KVA = greater risk
480V @ 10kA fault = 8 sticks of TNT
Employees need to be educated of the risks
Your electrical equipment must be labeled and maintained
You must perform an arc flash risk assessment per NFPA 70E-18, ref: sec.130.5
Reducing time and increasing space
The right equipment installed the correct way
To err is human!
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Some Milestones in History 1897—The National Electrical Code created
1956—Dalziel and electric shock research completed
1969—Burn research—Stoll Curve developed
1970—OSHA legislated into effect in USA
1976—NFPA 70E first published
1982—Arc flash and Ralph Lee’s paper reviewed
1995—NFPA 70E first references arc flash added
2000—NFPA 70E PPE requirements and hazard risk tables
2000—Incident energy calculations developed
2002—IEEE 1584 first version is published
2002—NEC and arc flash warning labels defined
2007—NESC—Arc flash and electric utilities standards
2009—NFPA 70E additional defined label requirements
2015—Removal of level 0 PPE
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The steps for proper labeling?
3 Phase Bolted Fault Current
Arcing Fault Currents(Incident Energy)
Device Operating Times